Machine for knocking out foundry moulding boxes



Jun 18, 1957 s, BEECH 2,795,828

MACHINE FOR KNOCKING OUT FOUNDRY MOULDING BOXES Filed NOV. 27, 195,3

3 Sheets-Sheet 1 ff 5/ 1d 12 2,795,828 MACHINE FOR KNOCKING OUT FOUNDRY MOULDING BOXES Filed Nov. 27, 1953 A.S.BEECH June 18, 1957 5 Sheets-Shegt 2 m AU Av nu nu nu nu m m m 0v June 18, 1957 CH 2,795,828

. MACHINE FOR KNOCKING OUT FOUNDRY MOULDING BOXES Filed Nov. 27, 1953 3 Sheets-Sheet 5 H T 7 F limited States Patent G MACHINE FOR KNOCKING OUT FOUNDRY MOULDING BOXES Austin Sidney Beech, Leighton Buzzard, England, assignor to Foundry Equipment Limited, Leighton Buzzard, England, a British company Application November 27, 1953, Serial No. 394,817 1 Claim. (Cl. 22,95.7)

This invention comprises improvements in or relating to machines for knocking out foundry moulding boxes.

It is an object of the invention to provide a process of, and apparatus for, knocking out foundry moulding boxes after the metal has been cast into the mould, and of increasing the speed at which such a process can be carried out.

According to the present invention apparatus for knocking out foundry moulding boxes comprises a massive base and upon the base a relatively light grille resiliently supported from the base and provided with means for vibrating it at high frequnecy.

In the use of this apparatus moulding boxes are placed upon the grille and, vibration being applied to the the grille, the sand in the moulding box falls out through the grille while the castings are retained upon the grille. The grille forms a convenient means on to which moulding boxes can be slid or to which they can be conveyed and the castings and moulding boxes can easily he slid off the grille when the sand has been knocked out so that much labour is saved.

In one form the massive base itself rests on rubber pads so that it does not transmit vibration to its supports.

The base may be so constructed that it can readily be fitted against a second base, and the grille is likewise such as to fit against another grille on the second base. This permits exceptionally large moulding boxes to .be dealt with where necessary. 1

By making the grille and its frame of a light structure and mounting it on rubber blocks of appropriate resiliency it is possible on repetition work to ensure that the moulding boxes when resting on the grille lead to a natural frequency vibration which is similar to that of the vibrators and, resonance being set up, the effect of the vibrators is increased.

It is a further object of the invention to provide an apparatus for knocking out foundry moulding boxes which can be incorporated in an automatic mould conveyor system.

To this end the invention comprises a machine for knocking out foundry mould boxes comprising a base structure, a frame yieldably mounted on the base structure so as to be capable of being shaken or vibrated thereon, which frame includes support members to support mould boxes for sliding movement along the frame and a floor beneath said support member to receive castings, moulding sand and the like falling out of mould boxes on the support members, and means to vibrate or shake the frame in such manner as to give mould boxes and other material thereon, in addition to a to-and-fro or shaking motion, a progressive motion towards one end of the frame. Thus mould boxes fed on to the frame at one end will travel slowly toward the other end, being subjected meanwhile to shaking or vibration so that their contents fall out on to the floor beneath, which contents are likewise caused to move toward {the end of the frame.

Preferably the floor consists of a grille with large openings such that the castings from the mould boxes will be retained thereon while the moulding sand, cores and the like fall through, and a second fioor is provided beneath the grille to receive the material falling through 2,7 95,8128 Patented June 18,1957

it. Said second floor may be a small mesh screen allowing fine moulding sand to pass through but retaining lumps of sand, cores, metallic inclusions and the like, a further floor being provided beneath the screen to receive the fine sand. The frame may comprise a trough with the floors secured at different levels between the sides of the trough.

The following is a description by way of example of certain constructions in accordance with the invention, reference being made to the accompanying drawings in which:

Figure l is a side elevation of one construction,

Figure 2 is a plane of the same,

Figure 3 an end elevation,

Figure 4 is a side elevation of a second construction with part of one of the base castings broken away upon the section line 4-4 of Figure 6 to show the rubber mountings,

Figure 5 is a central vertical section through the same, and

Figure -6 is a cross-section upon the line 6-6 ,of .Figure 4 looking in the direction of the arrows.

Referring first to the construction shown in Figures 1-3, a massive rectangular cast iron frame 11 isprovided with a large rectangular central opening 12 through which sand can fall. In the underside of this frame are eight recesses to receive rectangular rubber base blocks 13, two in each endand two in each side near the corners.

The longer sides 14 of the frame are nearly vertical on their outer faces and have sloping inner faces 15 like the sides of a hopper which descend to the opening 12 in the bottom. The ends of the frame are rectangular in cross-section, and at each end there are two projecting brackets 16 in the upper faces of which are cast semi-cylindrical recesses 17. The ends 18 of the frame between the two projecting brackets are made lower than the brackets 16 and the sloping sides 15 of the frame project substantially above the level of the brackets. In the four semi-cylindrical recesses in the brackets there are disposed four stout rubber rings 19 with their axes horizontal to act as resilient supports for the vibrating frame 20 which is about to be described.

The vibrating frame 20 is fabricated from sheet steel and comprises a grille-like structure of intersecting longitudinal bars 21 and transverse bars 22 of steel. The longitudinal bars 21 are set on edge fairly close together. For example, there may be about 15 of them in a width of two feet six inches. At their ends two of them 23, 24, which are longer than the others, are chamfered off so as to be inclined, with their longer edges at the top. Across the underneath chamfered portions there are welded in clined end plates which hold the structure together .and also constitute chutes to deliver sand downwards towards the opening 12 in the bottom of the base-frame. Across the top of the longitudinal bars 21, 23, 24 above described there are a number of transverse bars 22, 2 welded, say 10 or more in number, some of which (32) are raised substantially above the others to act as skid bars for a mould box being pushed onto the knockout and to enable rapid and free expansion ,of the contents below the mould box when being emptied.

On the underside of the chute-plates 25 at each end ,of the grille-frame, there are welded brackets which correspond in position with the brackets 16 on the ends of the cast iron base-frame. These brackets also contain semi-cylindrical recesses and they fit .on the top ,of the tubular rubber resilient blocks 19 already referred to. Also secured to the underside of the ends of the chuteplates, between the resilient blocks, are vibrator-mqtom 31, 34 one at each end. These serve to rotate at high speed, out-,of-balance weights (inside the motor-casings) and when they are operating the grille-frame is vibrated endwise on the tubular rubber blocks 19 by the out-ofbalance weights. Part of the brackets to which the vibrator-motors are secured are formed as hoods 35 to shield the motors from sand.

In this construction the grille-frame 21, 22 is violently vibrated and a moulding box, if placed upon it, will rapidly have the sand shaken out of it. The sand and castings fall out of the box onto the grille, the empty moulding box remaining on the raised skid bars 32 whence it can easily be removed; the castings, falling on the grille, can also easily be removed and the sand falls through the grille for reclamation. By standing two frames side by side a very large moulding box can be accommodated.

Referring now to the construction shown in Figures 4-6, two massive triangular section iron-base castings, 40, 41, each about nine feet long, are supported parallel to one another (if desired upon rectangular rubber pads as in the case or" Figures l-3) secured on suitable foundations, the rubber pads (if provided) entering recesses in the castings so as to hold them against horizontal sliding movement. The base castings 4041 are each provided with inwardly-directed flanges 42 at each end having recesses in which are retained rubber mountings 43 of tubular shape and fitted so that their axes are horizontal and at right angles to the direction of lie of the base castings. A fabricated steel trough 44 rides between the base-castings, the trough having external brackets 45 on each side which are provided with semicircular cups to fit over the tubular rubber mountings 43 and support and retain the trough in position; the trough is thus able, by virtue of the rubber mountings, to shake or vibrate in the longitudinal direction.

At each end of the trough is mounted a vibrator 46 comprising an out-of-balance weight rotated about a transverse axis by a high speed electric motor at 3,000 cycles per minute or thereabouts. The vibrators rotate in phase with one another and are arranged so that the contents of the trough, in addition to being shaken or vibrated, are caused to make a gradual progressive movement toward one end of the trough, the direction of movement being the same as the direction of movement of the balance weights when they are at the top positions in their travel.

The trough 44 is U-shaped in cross-section and has two floors 47, 48, secured between the sides of the trough at difierent levels above the trough-bottom; the lower of said two floors comprises a screen of small mesh, while the upper floor is a heavy fabricated grillage with large openings. Supported by the upper floor 48 are a pair of longitudinal rails 49, 50 which serve to carry the mould boxes 51 which are to be knocked out. Mould boxes are fed in succession on to these rails at one end of the trough from a conveyor, and the boxes are vibrated and caused to make a progressive movement towards the other end of the trough, the contents of each box being shaken out onto the heavy grillage 48 beneath. The castings from the boxes are retained on the grillage and travel along the trough thereon, but the moulding sand, cores, loose metallic particles and so forth pass through the grillage on to the small mesh screen 47, any large blocks of sand being broken down to some extent on the grillage. The main bulk of the sand, in a fine condition, drops through the small mesh screen 47 into the bottom of the trough, while the lumps of sand, scrap, metallic inclusion and so forth are retained on the screen 47. The material on the screen 47 and the hue sand in the bottom of the trough are discharged through openings 52, 53 in the floor of the trough at difierent places near the end thereof.

The spacing of the mould boxes 51 above the grillage by means of the longitudinal rails 49 on which the boxes rest allows the box contents to fall clear, and permits the bulk volume of the moulding sand to expand as the sand drops from the box. A pair of angle-iron members 54 are secured along the sides of the trough above the rails, to act as guides for the mould boxes and prevent them from falling over the sides of the trough.

It will be appreciated that, in addition to knocking out the mould boxes, the apparatus also serves the purpose of a sand cooler since the vibration keeps the sand in the bottom of the trough 44 continuously agitated thereby facilitating the dissipation of heat and escape of steam, which is normally present in the sand at the knock-out, quickly and economically at an early stage in the reconditioning of the sand.

The height of the knock-out trough 44 is made such that mould boxes can be pushed on to it off a low mould conveyor, but the whole trough is kept above floor level to allow the sand and material from the grillage to be discharged beneath the trough. The trough can be made to any suitable length to cater for different types of cast ing, and additional vibrations may be provided in longer versions of the trough. if desired, the trough may be given a slight fall to speed the movement of the contents.

It may in some cases be found advisable, in order to accelerate evacuation of the sand to provide holes at intervals along the floor of the trough 44 and to provide a conveyor belt to receive and carry away the sand which falls through.

The trough 44 is made light in comparison with the iron base castings 40, 41 and is so disposed on its rubber mountings as to give it some resonance, ensuring that the maximum intensity of vibration is transmitted to the mould boxes. Suitable conveyors can be provided to carry the empty mould boxes, castings, material on the grillage, and fine moulding sand away from the discharge end of the trough.

I claim:

Apparatus for knocking out foundry mould boxes comprising a massive base, a relatively light-weight vibrating frame which includes a grille mounted on the base, resilient connections between the frame and base, the said grille having large openings such that the castings from the mould boxes will be retained on the grille while the moulding sand, cores and the like fall through, a small mesh screen attached to the frame beneath the grille to pass fine moulding sand but retain lumps of sand cores and the like, a tray-like floor, beneath the said small mesh screen, to receive the fine sand, upstanding rails on the grille extending longitudinally of the frame from end to end thereof, said rails being close enough together to support a moulding box for knocking out purposes, rotary out-of-balance vibrators at each end of the frame synchronized and set in such relationship to each other as to tend to propel a moulding box supported on the rails along them from one end of the said frame to the other, and inwardly projecting guide'rails on the frame at the top thereof, above the grille and extending longitudinally of the frame and maintaining the moulding boxes in position on the said upstanding rails during the end to end movement of the moulding boxes along the upstanding rails.

References Cited in the file of this patent UNITED STATES PATENTS 1,455,907 Daman May 22, 1923 1,578,470 Robertson et al Mar. 30, 1926 1,700,868 Woodward Feb. 5, 1929 2,020,131 Behnke Nov. 5, 1935 2,222,299 Parks Nov. 19, 1940 2,652,605 Christensen Sept. 22, 1953 FOREIGN PATENTS 664,598 Great Britain Jan. 9, 1952 OTHER REFERENCES Page 485 Metal Industry, June 17, 1949. 

